Waukesha County Power Outage History
2014–2025 · Wisconsin
Average — typical outage frequency and duration nationally. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Aug 11, 2021 | 1 hrs | 45,425 (27%) | Thunderstorm Wind |
| Aug 11, 2021 | 0 hrs | 42,687 (26%) | Thunderstorm Wind |
| Aug 11, 2021 | 1 hrs | 41,617 (25%) | Thunderstorm Wind |
| Aug 11, 2021 | 1 hrs | 37,922 (23%) | Thunderstorm Wind |
| Aug 11, 2021 | 6 hrs | 36,584 (22%) | Thunderstorm Wind |
Over the 12 years from 2014 to 2025, Waukesha County recorded 1,243 distinct power outage events, averaging 3.2 hours per event.
The single worst outage on record in Waukesha County started August 11, 2021 (Thunderstorm Wind), lasting 1 hours and leaving up to 45,425 customers without power (27% of the county) at its peak.
July has historically been the worst month for outages in Waukesha County, with 176 events recorded during that month across the dataset.
Based on this history, Waukesha County earns a Reliability Grade of C, placing it in the 42nd percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Waukesha County's outage profile
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Similar counties in Wisconsin
Counties with the closest reliability grade and national percentile to Waukesha County.
| County | Grade | National percentile |
|---|---|---|
| Door County | C | 42nd |
| Portage County | C | 42nd |
| Waupaca County | C | 44th |
| Sawyer County | C | 44th |
| Jefferson County | C | 46th |
FAQ
How often does power go out in Waukesha County?
Between 2014 and 2025, Waukesha County recorded 1,243 outage events, averaging 3.2 hours each.
What is Waukesha County's reliability grade?
Waukesha County has a Reliability Grade of C, in the 42nd national percentile.
What was the worst power outage in Waukesha County?
The worst outage on record started August 11, 2021 (Thunderstorm Wind), lasting 1 hours and affecting up to 45,425 customers.